1. Field of the Invention
There are two types of perforating sewing machines. In the first type cloth is perforated in an earlier step and is hereinafter referred to as the earlier perforation type machine; in the second type, cloth is perforated in a later step and is hereinafter referred to as the later perforation type machine.
The present invention relates to a quick feeding driving unit in a perforating sewing machine which combines functions of earlier and later perforation types.
2. Description of Prior Art
One cycle of a series of successive perforating operations in the earlier perforation type machine comprises "SEWN CLOTH CLAMPING STEP", "BUTTON PERFORATING STEP", "CLOTH TENSIONING STEP", "FIRST QUICK FEEDING STEP", "SEWING STEP", "SECOND QUICK FEEDING STEP" and "SEWN CLOTH CLAMPING AND RELEASING STEP". One comparable cycle in the later perforation type machine comprises "SEWN CLOTH CLAMPING STEP", "CLOTH TENSIONING STEP", "FIRST QUICK FEEDING STEP", "SEWING STEP", "SECOND QUICK FEEDING STEP", "BUTTON PERFORATING STEP" and "SEWN CLOTH CLAMPING AND RELEASING STEP".
There is a difference between the earlier perforation type and the later perforation type in respect of that portion of one cycle of the operation which includes "FIRST AND SECOND QUICK FEEDING STEPS".
A conventional perforating sewing machine of the earlier perforation type is provided, as shown in FIG. 3, with a quick feeding crank shaft 2' rotatably supported by a bed 9 of a sewing machine. The quick feeding crank shaft 2' is always rotated during the operation of the sewing machine since a quick feeding gear 1 is rotatably driven in one direction by a rotational driving source (not shown). A worm wheel 4 fixed to one end of a cylinder member 27'A mounted on a pattern wheel shaft 27' rotatably supported by the bed 9 is meshed with a worm 3. An outer wheel 5a of a clutch 5 is secured by screw 6 to the other end of cylinder 27'A. The outer wheel 5a is always rotated during the operation of the sewing machine via the worm 3, the worm wheel 4 and the cylindrical member 27'A. A pattern wheel 28 is attached to the other end portion 27'B of the pattern wheel shaft 27'. The clutch 5 is, as illustrated in detail in FIGS. 4(a), 4(b), directed in one way and has a plurality of rollers 24 each urged in the direction of connection thereof by a spring 25 in the position between a plurality of cam surfaces 26a of a plurality of quick feeding clutch roller carriers 26 respectively fixed to the outer wheel 5a and the pattern wheel shaft 27'.
The first and the second quick feeding steps in the earlier perforation type sewing machine is described below.
As shown in FIG. 3, a cutting driving wheel is driven each time the sewn cloth is subjected to the perforating operation at the time of "BUTTON PERFORATING STEP" so that a cam 7a (projection) attached to the cutting driving wheel 7 pushes a roller 10a in the direction of the arrow A just before completion of the cutting operation. A quick feeding actuation lever 10 having the roller 10a is swung to rotate a quick feeding actuation lever shaft 11 which is integrated with the quick feeding actuation lever 10 and rotatably supported by the bed 9. With rotation of the quick feeding actuation lever shaft 11, a quick feeding actuation release lever 12 is swung so that a pin 13 of the quick feeding actuation release lever 12 forces a quick feeding actuation latch 14 rotatably supported by the bed 9 to rotate in the direction of the arrow B. As a result, a quick feeding actuation tooth stopper 15 provided on a stepped portion 14a of the quick feeding actuation clutch 14 is swung about a bolt 15c by a resilient force of a spring 16 in the direction of the arrow C whereby a recess 15a of the quick feeding actuation tooth stopper 15 engages with a quick feeding forked stepped screw 18 projected from an end of a quick feeding fork 17.
The quick feeding actuation tooth stopper 15 is driven via the crank 2'a of the quick feeding crank shaft 2' and a quick feeding tooth stopper crank 8 rotatably fixed to the bed 9 to move reciprocally in the direction of the arrow D--D' in the prescribed cycle. With the engagement of the recess 15a of the quick feeding actuation tooth stopper 15 and the quick feeding forked stepped screw 18, the quick feeding fork 17 and a quick feeding slide shaft 19 fixed to the quick feeding fork 17 slide together in the direction of the arrow D--D' relative to the bed 9 in the prescribed cycle. With the sliding operation of the quick feeding slide shaft 19, a stepped portion 21a of the quick feeding sliding shaft stopper 21 engages a corner 17b of the quick feeding fork 17 to prevent the quick feeding fork 17 from moving in the direction of the arrow D'. A spring 20 extends between a bracket 20b and the quick feeding fork 17. The bracket 20b is fixed to the quick feeding sliding shaft stopper 21 which is rotatably supported at the bed 9 at the one end thereof.
In this arrangement, when the quick feeding actuation tooth stopper 15 moves to the arrow D', the quick feeding actuation tooth stopper 15 is raised upward in the direction of the arrow E by the inclined surface 15b of the recess 15a and is returned in such manner as to be retained on the stepped portion 14a of the quick feeding actuation latch 14. At this time, the quick feeding fork 17 is moved in the direction of the arrow D.
With the motion of the quick feeding fork 17 toward the direction of the arrow D, a quick feeding clutch release sleeve 22 on the pattern wheel shaft 27' engaged with the quick feeding fork 17 slides in the direction of the arrow D so that a plurality of quick feeding clutch release levers 23 (three as shown in FIG. 4(a)), which have been moved outward by the quick feeding clutch release lever 22, are rotated about each shaft 23a in the direction of the arrow F. With the rotation of the quick feeding clutch release levers 23, each roller 24 pressed by the corresponding quick feeding clutch release lever 23 is pushed by the spring 25 and enters between the outer wheel 5a of the clutch and the cam surface of the quick feeding clutch roller carrier 26 to engage the clutch 5 whereby the quick feeding clutch roller carrier 26 fixed to the pattern wheel shaft 27' starts to rotate together with the outer wheel 5a of the clutch 5.
With engagement of the clutch 5, the other end 27'B of the pattern wheel 27 integrated with the quick clutch roller carrier 26 starts to rotate so that the pattern wheel 28 fixed to the pattern wheel shaft 27' is rotated. A work clamping carrier (not shown) slidably supported by the bed 9 is moved in accordance with the rotation of the pattern wheel 28 to feed the sewn cloth placed on a pair of base plates on the work clamping carrier whereby "FIRST QUICK FEEDING STEP" is carried out.
When "FIRST QUICK FEEDING STEP" causes rotation of the pattern wheel secured to the pattern wheel shaft 27', a cam 32 attached to the pattern wheel 28 causes a quick feeding sliding shaft moving stopper release arm 29 to swing in the direction of the arrow G to push down the tip end of the quick feeding sliding shaft moving stopper 21 whereby the stepped portion 21a is disengaged from the corner 17b of the quick feeding fork 17. As a result, the quick feeding sliding shaft 19 and the quick feeding fork 17 integrated therewith are moved in the direction of the arrow D' by the compression spring 30. Accompanied by this operation, the quick feeding clutch release sleeve 22 forces each quick feeding clutch release lever 23 to move outward in the direction of the arrow F' as shown in FIG. 4(a) to decrease the resilient force of the spring 25 so that each roller 24 is pressed inside whereby the clutch is disengaged to complete the "FIRST QUICK FEEDING STEP".
The "SECOND QUICK FEEDING STEP" is made to utilize a disengagement of the clutch of the lower shaft wherein the second quick feeding actuation lever 31 is raised to rotate the quick feeding actuation lever shaft 11 to thereby feed quickly the sewn cloth in the same manner as the "FIRST QUICK FEEDING STEP" thereafter. Completion of the "SECOND QUICK FEEDING STEP" is made in such manner that the cam 32 attached to the pattern wheel 28 rotates the quick feeding sliding shaft moving stopper release arm 29 in the direction of the arrow G and thereafter in the same manner as the "FIRST QUICK FEEDING STEP".
The "FIRST QUICK FEEDING STEP" and the "SECOND QUICK FEEDING STEP" in the conventional later perforation type sewing machine is described below with reference to FIGS. 3, 5 and 6.
The "FIRST QUICK FEEDING STEP" utilizes a closing lever 33 which is operated in the "CLOTH TENSIONING STEP". That is, a quick feeding actuation lever latch 36 rotatably attached to the tip end of the quick feeding actuation lever 34 secured to the quick feeding actuation lever shaft 11 is positioned and capable of engagement with the pin 33a projected from the lower end of the closing lever 33. First, at the time the sewn cloth is clamped by a clamping unit, (not shown) the closing lever 33 is swung to cause the pin 33a to push and rotate the quick feeding actuation lever latch 36 as shown in FIG. 6(b), then to move over the quick feeding lever latch 36 as shown in FIG. 6(c) while the quick feeding actuation lever latch 36 is quickly returned to the original position. This action causes contact with the stopper 35 by the return spring (not shown), so that the quick feeding actuation lever 34 per se does not swing. Next, at the time when the closing lever 33 is swung into the direction of the arrow H' to effect the "CLOTH TENSIONING STEP", the pin 33a at the right side of the quick feeding actuation lever latch 36 is moved toward the arrow H'. At this time, since the quick feeding actuation lever latch 36 is engaged with the stopper 35, the quick feeding actuation lever 34 is swung in the direction of the arrow I' to rotate the quick feeding actuation lever shaft 11. Thereafter, in the same manner as the "FIRST QUICK FEEDING STEP" of the earlier perforation type, the "FIRST QUICK FEEDING STEP" can be carried out. At the same time, the "SECOND QUICK FEEDING STEP" utilizes the disengagment of the clutch on the lower shaft (not shown) upon completion of the "SEWING OPERATION" for raising the second quick feeding actuation lever 31 as shown in FIG. 3 to rotate the quick feeding actuation lever shaft 11 whereby the "SECOND QUICK FEEDING STEP" is carried out in the same manner as that of the earlier perforation type machine.
However, the conventional quick feeding driving unit of either the earlier perforation type machine or the later perforation type machine requires a complex arrangement and much labor and time for assembly and adjustment thereof.
Furthermore, inasmuch as the quick feeding mechanism of the conventional sewing machine is used exclusively either for the earlier perforation type machine or the later perforation type machine, if the single sewing machine employs functions of both the earlier and the later perforation type machines, the quick feeding mechanism becomes more complicated.